also update `HEAD` to set the specified branch as the current
branch.
-'git checkout' [<branch>]::
+'git checkout' <branch>::
+ To prepare for working on <branch>, switch to it by updating
+ the index and the files in the working tree, and by pointing
+ HEAD at the branch. Local modifications to the files in the
+ working tree are kept, so that they can be committed to the
+ <branch>.
++
+If <branch> is not found but there does exist a tracking branch in
+exactly one remote (call it <remote>) with a matching name, treat as
+equivalent to
++
+------------
+$ git checkout -b <branch> --track <remote>/<branch>
+------------
++
+You could omit <branch>, in which case the command degenerates to
+"check out the current branch", which is a glorified no-op with a
+rather expensive side-effects to show only the tracking information,
+if exists, for the current branch.
+
'git checkout' -b|-B <new_branch> [<start point>]::
-'git checkout' [--detach] [<commit>]::
- This form switches branches by updating the index, working
- tree, and HEAD to reflect the specified branch or commit.
-+
-If `-b` is given, a new branch is created as if linkgit:git-branch[1]
-were called and then checked out; in this case you can
-use the `--track` or `--no-track` options, which will be passed to
-'git branch'. As a convenience, `--track` without `-b` implies branch
-creation; see the description of `--track` below.
+ Specifying `-b` causes a new branch to be created as if
+ linkgit:git-branch[1] were called and then checked out. In
+ this case you can use the `--track` or `--no-track` options,
+ which will be passed to 'git branch'. As a convenience,
+ `--track` without `-b` implies branch creation; see the
+ description of `--track` below.
+
If `-B` is given, <new_branch> is created if it doesn't exist; otherwise, it
is reset. This is the transactional equivalent of
that is to say, the branch is not reset/created unless "git checkout" is
successful.
+'git checkout' --detach [<branch>]::
+'git checkout' <commit>::
+
+ Prepare to work on top of <commit>, by detaching HEAD at it
+ (see "DETACHED HEAD" section), and updating the index and the
+ files in the working tree. Local modifications to the files
+ in the working tree are kept, so that the resulting working
+ tree will be the state recorded in the commit plus the local
+ modifications.
++
+Passing `--detach` forces this behavior in the case of a <branch> (without
+the option, giving a branch name to the command would check out the branch,
+instead of detaching HEAD at it), or the current commit,
+if no <branch> is specified.
+
'git checkout' [-p|--patch] [<tree-ish>] [--] <pathspec>...::
When <paths> or `--patch` are given, 'git checkout' does *not*
<2> take a file out of another commit
<3> restore hello.c from the index
+
+If you want to check out _all_ C source files out of the index,
+you can say
++
+------------
+$ git checkout -- '*.c'
+------------
++
+Note the quotes around `*.c`. The file `hello.c` will also be
+checked out, even though it is no longer in the working tree,
+because the file globbing is used to match entries in the index
+(not in the working tree by the shell).
++
If you have an unfortunate branch that is named `hello.c`, this
step would be confused as an instruction to switch to that branch.
You should instead write: